1. Field of the Invention
This invention relates to the field of sanding apparatus and more particularly, to the field of multi-piece sanding wheels.
2. Discussion of the Background
Sanding wheels are widely used in a number of industrial applications to finish wood and other materials. In a typical operating setup, the sanding wheel is mounted on a drive motor and rotated about an axis as the piece to be worked is moved by it. The sanding wheel itself may be of any number of designs including single and multi-piece ones. In single piece designs, the sanding element and its backing portion are simply combined into an integral unit. In multi-piece designs, a common approach is to have a sanding member which includes a sanding strip and a contoured or profiled backing portion wherein the strip is positioned about the periphery of the backing portion. The planar or flat strip then assumes the profile of its backing portion. Alternately, the sanding strip itself can be contoured and mounted about a non-profiled backing portion.
In high volume operations, it is critical that the design of the sanding wheel not only permit its sanding element (e.g., a strip of sandpaper) to be easily and quickly removed and replaced once it is worn but also permit the backing portion or portions to be quickly and easily removed and replaced. That is, in large volume operations, downtime to replace worn sanding elements or to replace one profiled backing portion with another is absolutely crucial to a successful and efficiently run shop. In this regard and if the sanding station is simply one in a line of operations, then essentially the entire assembly or processing line must be shut down while the changes are made to the sanding wheels. Current sanding wheels do not permit quick changeouts and in particular, do not permit a quick change of a worn sanding element on a wheel or a quick change of one profiled backing portion for another.
For example, with the design of U.S. Pat. No. 4,870,787 to Voorhees which uses a continuous sanding strip, the strip can only be changed by loosening the entire wheel from its drive, separating the top and bottom halves of the wheel, inserting the sanding strip between the halves, and then re-tightening the halves together and onto the drive. The downtime to do such a change is obviously quite substantial particularly since the entire sanding wheel must be removed from its drive each time the sanding strip is changed or a new profile is needed.
In a companion U.S. Pat. No. 4,744,180, Voorhees discloses a sanding wheel in which his continuous sanding strip can be replaced without removing the entire wheel from its drive. However, even this method involves a time consuming and elaborate operation of threading a continuous sanding strip through a slot in circumferential lips extending about the wheel. It further involves securing the strip ends in place with a spring-biased clamp projecting outwardly from the main body of the wheel. Additionally, like his earlier patent, Voorhees' design requires that the wheel be disconnected from its drive to change out the backing portions for the sanding strip should different backing portions be desired or necessary. In a similar design of Larick Machinery, Inc., a continuous sanding strip with one part of a hook-loop fastener on its back is removably secured about a substantially cylindrical, backing portion which has the mating part of the hook-loop fastener about its periphery. However, to secure the ends of the strip on the backing portion, a large notch or gap is provided in the periphery of the backing portion into which the ends of the strip must be manually inserted. This notch is understandably rather large and creates a very undesirable gap in the otherwise continuous sanding periphery of the wheel. Additionally, the process of manually inserting the ends of the strip into the notch not only is time consuming but also creates bends or folds in the sanding strip which easily fatigue and break in use. Also, to replace the backing portion of the sanding strip (e.g., to go to a different profile), the drive must be disconnected from the backing portion and reconnected to the new backing portion resulting in significant downtime.
With the above background in mind, the multi-piece sanding wheel of the present invention was developed. With it, the sanding elements or strips can be easily and quickly removed and replaced without disconnecting the drive from the wheel. Additionally, the backing portions for the sanding strips can also be easily and quickly removed and replaced without disconnecting the drive from the wheel. In this manner, undesirable downtime to change worn sanding strips or to change profiles is significantly reduced.